God one day said to Moses in secret: ‘Go and get a word of advice from Satan.’

So Moses went to visit Iblis and when he came to him and asked for a word of advice,
‘Always remember,’ said Iblis, ‘this simple axiom: never say “I,” so that you never may become like me.’

So long as there remains in you a little of self-love you will partake of infidelity.
Indolence is a barrier to the spiritual way; but if you succeed in crossing this barrier, a hundred ‘I’s will break their heads in a moment.
Everyone sees your vanity and self-pride, your resentment, envy, and anger, but you yourself do not see them.
There is a corner of your being full of dragons and by negligence you are delivered up to them;
and you pet them and cherish them night and day. So, if you are aware of your inner state, why do you remain so listless!

—Farid ud-Din Attar, The Conference of the Birds, 1974 (London), Routledge & Keegan Paul Ltd., pp. 87.